adding stock levels together

[bloody_football]

I have a database which seems to open many copies when it is accessed over the internet (via ASP) but If I open it on my compter over my LAN then it seems to open 'exclusive' and those on the Internet get the error message that 'file is already in use'.

So I have devised a method where I will make a copy of my database on my computer, clear all the stock levels and then add in the new stock.
My question is - how do I write a query that adds the 2 stock levels together?

James

 

[bloody_football]

Sorry to have to bump this but I'm stuck until something can be done.